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Chemotaxis and degranulation of polymorphonuclear leukocytes in the presence of sulfide
S Persson1, R Claesson, J Carlsson
1Department of Oral Microbiology, University of Umeå, Sweden.
Abstract:
In polymicrobial infections such as periodontal disease, the polymorphonuclear leukocytes (PMN) may have to work in the absence of oxygen and in the presence of significant levels of hydrogen sulfide. There are conflicting results reported on the chemotactic capacity of PMN under anaerobic conditions. It is not known whether PMN are able to migrate and release the contents of their granules in the presence of sulfide. PMN were exposed to various levels of sulfide and their chemotaxis and degranulation were studied when they were stimulated with N-formyl-methionyl-leucyl-phenylalanine or zymosan-activated serum. Chemotaxis was evaluated with the agarose method. The release of granule markers, lactoferrin and myeloperoxidase, was evaluated with enzyme-linked immunosorbent assay. PMN had similar capacity for chemotaxis under aerobic and anaerobic conditions. The migration of PMN was only to a minor extent inhibited by 1-2 mM sulfide. The release of lactoferrin and myeloperoxidase was the same under aerobic and anaerobic conditions and was not significantly influenced by sulfide. PMN seem to be very well suited to defend the tissue against bacteria under the harsh conditions prevailing in the periodontal pocket.
Insights
Polymorphonuclear leukocytes (PMN) effectively combat bacteria in anaerobic, sulfide-rich environments like periodontal pockets. Their migration and degranulation remain functional, demonstrating resilience in harsh conditions.
Area of Science:
- Immunology
- Microbiology
- Oral Biology
Background:
- Polymicrobial infections, like periodontal disease, create challenging environments for immune cells.
- Immune cells, specifically polymorphonuclear leukocytes (PMN), must function under anaerobic conditions and in the presence of hydrogen sulfide.
- Previous research on PMN function in these conditions yielded conflicting results.
Purpose of the Study:
- To investigate the chemotactic capacity and degranulation of PMN under anaerobic conditions.
- To determine the impact of hydrogen sulfide on PMN migration and granule release.
- To assess the overall effectiveness of PMN in defending tissues during polymicrobial infections.
Main Methods:
- PMN were exposed to varying concentrations of sulfide.
- Chemotaxis was measured using the agarose method.
- Degranulation, indicated by the release of lactoferrin and myeloperoxidase, was assessed via enzyme-linked immunosorbent assay (ELISA).
- PMN were stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP) or zymosan-activated serum (ZAS).
Main Results:
- PMN exhibited comparable chemotactic capacity under both aerobic and anaerobic conditions.
- Sulfide at 1-2 mM concentrations only slightly inhibited PMN migration.
- The release of lactoferrin and myeloperoxidase was unaffected by anaerobic conditions or sulfide exposure.
- PMN degranulation remained consistent regardless of oxygen availability or sulfide presence.
Conclusions:
- PMN maintain robust chemotaxis and degranulation capabilities in the presence of sulfide and under anaerobic conditions.
- These findings suggest PMN are well-equipped to combat bacterial infections in challenging microenvironments, such as the periodontal pocket.
- PMN play a crucial role in tissue defense within harsh conditions prevalent in oral infections.